Wikipedia
Eldfell is a composite volcanic cone just over high on the Icelandic island of Heimaey. It formed in a volcanic eruption which began on the eastern side of Heimaey in the Westman Islands on 23 January 1973. This came without any sign of warning. The name of Eldfell means Mountain of Fire in Icelandic.
The eruption caused a major crisis for the island and nearly led to its permanent evacuation. Volcanic ash fell over most of the island, destroying around 400 homes, and a lava flow threatened to close off the harbour, the island's main income source via its fishing fleet. An operation was mounted to cool the advancing lava flow by pumping sea water onto it, which was successful in preventing the loss of the harbour.
After the eruption, the islanders used heat from the cooling lava flows to provide hot water and to generate electricity. They also used some of the extensive tephra, fall-out of airborne volcanic material, to extend the runway at the island's small airport, and as landfill, on which 200 new houses were built.